A Windsor Terrace resident stumbled upon two black trash bags of discarded goat or deer parts — the latest evidence that a demented animal killer is slaughtering beasts and then dumping them in Brooklyn’s most beloved park.

The two sacks of detritus — one filled with guts, the other containing a gutted and decapitated deer or perhaps goat — were at the edge of the park near Parkside Avenue and Parade Place, about 30 feet from each other.

“I initially thought it was a dog,” said Alex Gurevich, who first eyed — or, more accurately, nosed — the bags on Sunday.

Whatever it was, it was certainly no surprise to park-lovers, many of whom have watched with increasing disgust the almost monthly incidents that began last March when some rocks along the park’s lakefront were found covered in blood.